MGDI based parallel adder for low power applications

Abstract

The paper discusses a unique method to design low power circuits, which is called Gate Diffusion Input (GDI) method. Complex functions can be implemented using only two transistors by using this method. GDI technique allows for reduced power consumption, lower delay, lesser transistor count and decreased area of circuits. It also makes the system design less complex. Full adders and parallel adders, are major building blocks of different digital components like ALUs, DSPs etc. Hence, reducing power consumption of adders is very important. This work aims at building a parallel adder that consumes less power. A GDI based XOR gate is designed using which, a 10T full adder is designed which involves lesser number of devices compared to CMOS Full adder. The threshold loss in full adder is a major pitfall. A standard CMOS process compatible version of GDI cell, modified GDI, mGDI cell is proposed, using which a full adder is built. A 4-bit parallel adder is designed. The proposed technique consumes lesser area and has low power dissipation compared to CMOS design. Power consumption is reduced by 15% compared to CMOS design. Cadence tool at 180 nm is used to implement the designs.